21142135 has 16 divisors (see below), whose sum is σ = 30701376. Its totient is φ = 13644288.

The previous prime is 21142127. The next prime is 21142139. The reversal of 21142135 is 53124112.

It is not a de Polignac number, because 21142135 - 2³ = 21142127 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21142139) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17172 + ... + 18361.

It is an arithmetic number, because the mean of its divisors is an integer number (1918836).

Almost surely, 2^21142135 is an apocalyptic number.

21142135 is a deficient number, since it is larger than the sum of its proper divisors (9559241).

21142135 is a wasteful number, since it uses less digits than its factorization.

21142135 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35562.

The product of its digits is 240, while the sum is 19.

The square root of 21142135 is about 4598.0577421342. The cubic root of 21142135 is about 276.5134625410.

Adding to 21142135 its reverse (53124112), we get a palindrome (74266247).

The spelling of 21142135 in words is "twenty-one million, one hundred forty-two thousand, one hundred thirty-five".